i wouldn't even think of a show cage dude!! u might as well get on that does its job!! if u can find one look out for the MSV half cages!! they do come up for sale every now and then!! i got one and it looks the nuts!! a good cage if u dont wanna go for a full roll cage!!
H&R's!! i would defo consider them m8!! for the cash u cannot go wrong and they really do transform how the car drives!! also get them set up properly!!
for an exhaust system i would go for something like a Miltec or Janspeed, something like this over a custom Powerflow system!! and if u do the cat back do the de cat too!! make most the difference IMO
wheels wise it is down to preference!! i hav White Turini's on my cup and they look the nuts!!
dude if it helps here is a few pics on the wheels and cage!! oh and my car is on H&R's too!!